The present invention relates generally to wireless, packet-hopping networks, and more particularly, to a method for installing a wireless, packet-hopping network.
A network which consists of a plurality of nodes which communicate with each other and with a control node (also referred to as "main" or "central" node) via wireless (RF) links is generally referred to as a wireless (or radio) network. In wireless, packet-hopping networks, each node includes a node controller which includes a digital signal processing device (e.g., a microprocessor) and an RF transceiver. Data is communicated (transferred) between the individual nodes and the control node by a technique known as "packet hopping", in which individual "packets" of data are transferred from the control node to a destination node and from an origin node to the control node by being hopped from node-to-node in accordance with a network routing protocol.
"Packets" are logical units of data typically ranging in size from about 5-1000 bytes. Generally, these packet-hopping data communications are carried out under the control of the control node, which is typically a computer on which resides the data communications control software. The packet-hopping data transfer scheme enables a reduction in the cost of the RF transceivers and compliance with FCC Part 15 requirements.
Such wireless, packet-hopping networks are particularly suitable for controlling one or more functions or systems of a building, e.g., the lighting, HVAC, and/or security systems of the building, because a wireless network offers a low-cost, indoor communication infrastructure that does not require new lines to be added to the existing structure in order to carry the network information. Further, such networks can support additional systems installed in the building, such as paging, heating control, air conditioning control, and personal communications systems.
The control node of such building control networks is typically a programmable controller or building computer. The individual nodes and the building computer run different software programs which are complementary, and which together constitute the system control software. The individual nodes are typically distributed throughout the building to monitor the status/value of prescribed parameters of the building system being controlled, and to produce control signals in response to commands issued by the building computer to adjust the prescribed parameters as required. It is important that the building computer be able to send and receive data to and from each node in the network in order to properly monitor the status/value of the prescribed parameters, and to issue commands to adjust the prescribed parameters as required, in accordance with the system control software.
An exemplary building control network is an automatic or intelligent lighting control system which monitors lighting levels, occupancy status, energy consumption as a function of time, and/or other lighting parameters of each room and/or area of the building within the network, i.e., each room and/or area of the building which is equipped with a lighting module(s) linked to a node controller (also referred to as a "wall unit") which includes an RF transceiver, a digital signal processing device (e.g., microcontroller or microprocessor), and control circuitry to signal the lights to change brightness levels. Each lighting module and its associated node controller together constitute a node in the network which is under the control/management of the building computer.
In such an intelligent lighting control system, each of the lighting modules is preferably individually programmable (e.g., by building occupants), via its associated wall unit, to provide direct control of the setting of the dimming ballast thereof, and thus, direct control of the lighting level of the lamp(s) thereof. In this regard, each of the nodes includes one or more sensors (e.g., occupancy status, daylight (ambient lighting), and dimming/lighting level sensors) which provide sensor feedback data to the digital signal processing device (e.g., a microprocessor) of the node controller, which is programmed to analyze (process) the sensor feedback data and to generate control signals for adjusting the lighting level of the monitored lamp(s) associated therewith, as required, to achieve the programmed local lighting conditions.
The sensor feedback data is also transmitted by each node in the network to the building computer, when requested by the building computer to do so, or when the local lighting conditions change. The building computer analyzes (processes) the sensor feedback data in accordance with lighting system control software loaded therein, and sends control data (commands) to the individual nodes, as required, in order to adjust the lighting levels of the monitored rooms/areas of the building in accordance with the lighting system control software, e.g., to optimize the energy efficiency of the lighting system, and thereby override the programmed lighting levels provided by the individual lighting modules. Thus, in addition to being individually programmable and being capable of independent operation, the distributed modules are functionally integrated into a single building-wide network under the control of the building computer.
Data communications in such networks are generally between the building computer and the individual nodes, and vice versa, over a common communications channel, in accordance with a network routing protocol. The data is transferred in packets from the building computer to a destination node outside of the immediate transmitting range of the building computer (i.e., not directly "linked" or "connected" to the building computer) by hopping or relaying each packet from node-to-node until the packet reaches the destination node. Each of the nodes which hops or relays a packet to one or more other nodes in the network is commonly referred to as a "repeater node", or simply, "repeater". The destination node generally acknowledges receipt of a data packet from the building computer by returning an acknowledgement data packet to the building computer via one or more repeaters in a similar fashion.
Advantageous network routing algorithms are disclosed in co-pending U.S. patent application Ser. No. 08/558,447, filed Nov. 16, 1995, in the name of A. Dasgupta, which is assigned to the assignee of the present invention, and co-pending U.S. patent application Ser. No. 08/608,910, filed Feb. 29, 1996, in the name of George A. Melnik, which is also assigned to the assignee of the present invention. The disclosures of both of these applications are herein incorporated by reference.
The installation of a building control network entails the physical placement and powering-up of each node in the network. Prior to the advent of the present invention, the address of each node in the network and the default parameters for each node were preprogrammed at the time of manufacture (i.e., "factory-set"), and not set at the time of installation. However, the preprogramming of nodes at the time of manufacture (i.e., prior to installation in a particular building), necessitates that long addresses (e.g., 100 bits or more) be used to ensure that all manufactured nodes are provided with a unique address. Such long addresses reduce the efficiency of data communications over the common network communications channel.
In this connection, since a typical network only has a few hundred nodes, it is only necessary to employ addresses which are 7-10 bits long in order to ensure that each node in the network is assigned a unique address (as long as no other nearby building with a similar system is within the transmitting range of the network, in which case, a building identifier code can be added to the address of each node, or the networks in the different buildings can be operated on different channels). Clearly, the use of shorter node addresses would significantly enhance the data communications efficiency of the wireless network. Thus, site specific addressing of the nodes at the time of installation would be superior to the technique of preprogramming the node addresses. As will become apparent hereinafter, the present invention, in one of its aspects, provides this capability.
Prior to the advent of the present invention, the preprogrammed default settings of the individual nodes in the wireless network could only be changed via commands issued by the building computer. This significantly limits the flexibility and significantly increases the cost of installation of the wireless network. Thus, the capability of directly programming each of the nodes at the time of installation would enhance the flexibility and decrease the cost of installation of the wireless network. As will become apparent hereinafter, the present invention, in another of its aspects, also provides this capability.
To complete the installation, the installer must determine the address of each node in the network, and then input into the building computer, for each node in the network, the address of that node and location identification data (e.g., room number) indicative of the physical location of that node within the building. At present, the complexity of this procedure increases the required time and cost for installation of the network. As will become apparent hereinafter, the present invention, in another of its aspects, simplifies this procedure, and reduces the required time and cost for this procedure.
After the nodes and building computer are installed, the wireless network is then initialized, in order to provide the building computer with nodal connectivity information which the network communications protocol requires in order to route packets of data through the network by the above-described packet-hopping technique. The nodal connectivity information includes information as to which nodes in the network are able to communicate with each other. The building computer formulates routing tables on the basis of the nodal connectivity information which it gathers during the network initialization process. The building computer then uses these routing tables to transfer packets of data from the building computer to a destination node and from an origin node to the building computer by hopping the packets from node-to-node along a route which it determines from the routing tables to be the most efficient route available at that time.
An advantageous automatic initialization scheme is disclosed in co-pending U.S. patent application Ser. No. 08/579,650, filed on Dec. 27, 1995, in the name of George A. Melnik, and assigned to the assignee of the present invention, the disclosure of which is herein incorporated by reference.
As feedback to the user (typically the building operations personnel), the physical configuration of the wireless network can be displayed on the monitor of the building computer, e.g., by illustrating the physical location of each node on a floor plan of the building. In this connection, the links between the nodes of the network can be automatically drawn during the initialization routine, to thereby provide a graphical representation of the wireless network for diagnostic and operational purposes.
Prior to the advent of the present invention, the operation of each of the individual nodes could only be verified during (or after) network initialization. Consequently, any malfunction or improper operation of a given node could only be detected or diagnosed after the entire network was installed and tested.
Clearly, it would be advantageous to have the capability of testing or verifying the operation of the nodes at the time that they are installed, to thereby facilitate correction of any diagnosed error or replacement of the node before completion of the installation of the entire network, and prior to execution of the initialization routine. Such a capability would reduce the required time and cost for network initialization, and would minimize network communications difficulties. As will also become apparent hereinafter, the present invention, in another of its aspects, also provides this capability.